Fix reading back id field value when multiple id property candidates exist.

We now check if a property identifies as the entities id property when populating values read from the source document.

Original pull request: #4878
Closes #4877

Author: christophstrobl

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/convert/MappingMongoConverter.java

@@ -134,7 +134,7 @@ public class MappingMongoConverter extends AbstractMongoConverter
 	private static final BiPredicate<MongoPersistentEntity<?>, MongoPersistentProperty> PROPERTY_FILTER = (e,
 			property) -> {
 
-		if (property.isIdProperty()) {
+		if (e.isIdProperty(property)) {
 			return false;
 		}
 

spring-data-mongodb/src/test/java/org/springframework/data/mongodb/core/convert/MappingMongoConverterUnitTests.java

@@ -3313,6 +3313,21 @@ void projectShouldReadComplexIdType(Class<?> projectionTargetType) {
 				.extracting("id").isEqualTo(idValue);
 	}
 
+	@Test // GH-4877
+	void shouldReadNonIdFieldCalledIdFromSource() {
+
+		WithRenamedIdPropertyAndAnotherPropertyNamedId source = new WithRenamedIdPropertyAndAnotherPropertyNamedId();
+		source.abc = "actual-id-value";
+		source.id = "just-a-field";
+
+		org.bson.Document document = write(source);
+		assertThat(document).containsEntry("_id", source.abc).containsEntry("id", source.id);
+
+		WithRenamedIdPropertyAndAnotherPropertyNamedId target = converter.read(WithRenamedIdPropertyAndAnotherPropertyNamedId.class, document);
+		assertThat(target.abc).isEqualTo(source.abc);
+		assertThat(target.id).isEqualTo(source.id);
+	}
+
 	org.bson.Document write(Object source) {
 
 		org.bson.Document target = new org.bson.Document();
@@ -4531,4 +4546,10 @@ public DoubleHolderDto(DoubleHolder number) {
 		}
 	}
 
+	static class WithRenamedIdPropertyAndAnotherPropertyNamedId {
+
+		@Id String abc;
+		String id;
+	}
+
 }